The present invention relates generally to locks, especially padlocks and other key-operated locks, and relates more particularly to a novel internal locking mechanism which substantially eliminates the possibility of unauthorized opening of the lock by means of "picking".
Conventional padlocks are widely used in a diversity of applications, representing one of the most common forms of known security locks. Typically, such padlocks comprise a lock body which supports internally a series of rotatable or otherwise movable tumblers controlled by means of a compatibly profiled key insertable into the tumbler assembly through a keyway in the lock body to release and fee one end of a shackle from the lock body when the key properly moves the tumblers into "unlocked" alignment with one another and to otherwise retain the shackle in a "locked" position withdrawn within the lock body. Over the years, advances in metallurgy and hardening techniques have enabled the lock body and shackle to be fabricated of metals which substantially resist cutting and other forms of attempted tampering, thereby improving the security of such locks. Other forms of improvements have been undertaken with regard to the internal locking mechanism itself. However, one disadvantage suffered by substantially all conventional tumbler-type locks intended to be operated only by compatibly profiled keys is that only a moderate amount of skill is required of a person knowledgeable in the construction of such locks to manipulate the tumblers of the locks using a pin or similar device inserted into the keyway and thereby open such a lock without its associated control key, a practice commonly referred to as "picking" the lock.